91-622 Removal/installation of control unit for airbags and belt
tensioners (from 09/87 onwards)
Special tools
Commercially available tools
Ratchet (1/4") Part No. 415 e.g. Eduard Wille GmbH
Connector (1/4") Part No. 412 Postfach 12 01 03
D-5600 Wuppertal 12
Testing
-------------------------------
After completing operations on the driver's
airbag/belt tensioner restraint system, the
system must be tested with an impulse
display.
The test procedure is described at the end of
the job number.
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P91-0023-61
Removal
Ignition (1) Switch off.
Negative battery terminal Disconnect and insulate.
Passenger's footwell floormat Remove.
Plastic nut on footrest (2), wrench size 8 Remove.
Red 10-pin plug, airbag (X29/9) Disconnect.
Ashtray Remove
Two cross-slot screws in ashtray housing (4) Remove
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Ashtray housing and storage tray (6) Remove.
Radio (5) Remove.
Plug connector on control unit Disconnect.
Two cross-slot screws on control unit (7) Remove.
Control unit Remove.
Installation note
Arrow on control unit must point towards
front of vehicle.
Install in reverse order.
Testing after control unit replacement
Impulse counterconnecting
diagram, Model 126
013 Impulse counter
G1 Battery
X92 Test connection for
8-pole diagnostics
(flasher code)
1913-15443
A diagnostic program is incorporated in the
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control unit which checks both the unit itself
and the airbag system components. If a fault
is identified, either the control lamp (A1e15)
will not go out after 4 seconds or it will come
on when the vehicle is being driven. The fault
is memorized and can be checked as an
impulse display via control lamp (A1e15) or
digitally by means of an impulse counter.
Note on impulse display
The impulse counter display panel shows
numbers 1-10.
Number 1 signifies that no faults are stored
in the system memory. All the other digits are
assigned to specific faulty circuits. If more
than one fault is present in the system, the
fault with the lowest impulse number is
indicated first.
If, after connection, the LED U-Batt
lights up, the impulse counter and power
supply to the impulse counter are in
order.
When, during testing, the first number
reappears after at least two or more
impulse displays (digits) all the faults
have been indicated.
Impulse display diagnosis
Connect impulse counter as shown in
connecting diagram.
Note
The LED U-Batt display in the display
panel must light up.
Switch on the ignition.
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Operate start button from 2 to 4 seconds.
Display 1 means no faults in system.
If another number appears, rectify fault
in accordance with Trouble Diagnosis
schedule.
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